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147 lines
5.0 KiB
147 lines
5.0 KiB
/* crypto/dh/dh_check.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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#include <stdio.h> |
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#include "cryptlib.h" |
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#include <openssl/bn.h> |
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#include <openssl/dh.h> |
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/*- |
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* Check that p is a safe prime and |
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* if g is 2, 3 or 5, check that it is a suitable generator |
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* where |
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* for 2, p mod 24 == 11 |
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* for 3, p mod 12 == 5 |
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* for 5, p mod 10 == 3 or 7 |
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* should hold. |
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*/ |
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int DH_check(const DH *dh, int *ret) |
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{ |
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int ok = 0; |
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BN_CTX *ctx = NULL; |
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BN_ULONG l; |
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BIGNUM *q = NULL; |
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*ret = 0; |
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ctx = BN_CTX_new(); |
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if (ctx == NULL) |
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goto err; |
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q = BN_new(); |
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if (q == NULL) |
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goto err; |
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if (BN_is_word(dh->g, DH_GENERATOR_2)) { |
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l = BN_mod_word(dh->p, 24); |
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if (l != 11) |
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*ret |= DH_NOT_SUITABLE_GENERATOR; |
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} |
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#if 0 |
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else if (BN_is_word(dh->g, DH_GENERATOR_3)) { |
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l = BN_mod_word(dh->p, 12); |
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if (l != 5) |
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*ret |= DH_NOT_SUITABLE_GENERATOR; |
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} |
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#endif |
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else if (BN_is_word(dh->g, DH_GENERATOR_5)) { |
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l = BN_mod_word(dh->p, 10); |
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if ((l != 3) && (l != 7)) |
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*ret |= DH_NOT_SUITABLE_GENERATOR; |
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} else |
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*ret |= DH_UNABLE_TO_CHECK_GENERATOR; |
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if (!BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL)) |
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*ret |= DH_CHECK_P_NOT_PRIME; |
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else { |
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if (!BN_rshift1(q, dh->p)) |
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goto err; |
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if (!BN_is_prime_ex(q, BN_prime_checks, ctx, NULL)) |
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*ret |= DH_CHECK_P_NOT_SAFE_PRIME; |
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} |
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ok = 1; |
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err: |
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if (ctx != NULL) |
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BN_CTX_free(ctx); |
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if (q != NULL) |
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BN_free(q); |
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return (ok); |
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} |
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int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret) |
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{ |
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int ok = 0; |
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BIGNUM *q = NULL; |
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*ret = 0; |
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q = BN_new(); |
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if (q == NULL) |
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goto err; |
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BN_set_word(q, 1); |
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if (BN_cmp(pub_key, q) <= 0) |
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*ret |= DH_CHECK_PUBKEY_TOO_SMALL; |
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BN_copy(q, dh->p); |
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BN_sub_word(q, 1); |
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if (BN_cmp(pub_key, q) >= 0) |
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*ret |= DH_CHECK_PUBKEY_TOO_LARGE; |
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ok = 1; |
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err: |
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if (q != NULL) |
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BN_free(q); |
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return (ok); |
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}
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